You say "people without guns" like that is possible. Even in the worst police states, like England, one can EASILY find illegal weaponry. The only ones whom the laws disarm is the law-abbiding citizens.
Of course, I meant in theory, anyone who wishes to do harm to another human being, is willing to die in the process, isn't completely idiotic, and doesn't talk about it, can accomplish it, a gun is just another way to accomplish said thing.
But banning guns from some places but allowing them in others is a horrible policy as well, I remember hearing a story somewhere, person goes into a restaurant, leaves his gun in his car due to a law, another guy goes in and starts shooting people.